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The title compound, C16H27Cl3N2O5, which is an enantiopure dipeptide trichloro­ethyl ester, adopts an extended conformation. The mol­ecules are linked via –NH...O=C hydrogen bonds into a unique β-spiral assembly along the c axis.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680502636X/ob6564sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S160053680502636X/ob6564Isup2.hkl
Contains datablock I

CCDC reference: 290313

Key indicators

  • Single-crystal X-ray study
  • T = 173 K
  • Mean [sigma](C-C) = 0.009 Å
  • R factor = 0.043
  • wR factor = 0.079
  • Data-to-parameter ratio = 15.7

checkCIF/PLATON results

No syntax errors found



Alert level B PLAT026_ALERT_3_B Ratio Observed / Unique Reflections too Low .... 32 Perc.
Author Response: Diffractions from the crystal of (I) were too weak to collect enough numbers, even we have used many techniques to increase the number data available (low temperature, Cu-K(alpha) radiationan, area detector).
PLAT220_ALERT_2_B Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       4.47 Ratio
Author Response: It is due to the difference of thermal mobility. The atoms located at chain-ends and amino-acid side chains often show higer U(eq) compared with the atoms located inside of the molecule.
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for       C101
Author Response: It is due to the difference of thermal mobility. The atoms (C102, C103, and C104) often show higer U(eq) compared with the atoms (C101 and C105) located inside of the Boc group.

Alert level C PLAT222_ALERT_3_C Large Non-Solvent H Ueq(max)/Ueq(min) ... 3.75 Ratio
Author Response: It is due to the difference of thermal mobility. The atoms located at chain-ends (Boc- and -OEt) and amino-acid side chains often show higer U(eq) compared with the atoms located inside of the molecule.
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for       C105
Author Response: It is due to the difference of thermal mobility. The atoms (C102, C103, and C104) often show higer U(eq) compared with the atoms (C101 and C105) located inside of the Boc group.
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          9
Author Response: The chain end atoms (such as Boc- and -OEt) often show lower bond precision due to their higher thermal mobility compared with the atoms located inside of the chain.
PLAT431_ALERT_2_C Short Inter HL..A Contact  Cl43   ..  O301    ..       3.02 Ang.

Alert level G REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF. From the CIF: _diffrn_reflns_theta_max 68.19 From the CIF: _reflns_number_total 4134 Count of symmetry unique reflns 2145 Completeness (_total/calc) 192.73% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 1989 Fraction of Friedel pairs measured 0.927 Are heavy atom types Z>Si present yes
Author Response: We have checked the number of Friedel pairs is correct.

0 ALERT level A = In general: serious problem 3 ALERT level B = Potentially serious problem 4 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 4 ALERT type 2 Indicator that the structure model may be wrong or deficient 3 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: RAPID-AUTO (Rigaku, 2003); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku, 2003); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP (Johnson, 1965); software used to prepare material for publication: CrystalStructure.

tert-Butoxycarbonyl-L-leucyl-L-alanine trichloroethyl ester top
Crystal data top
C16H27Cl3N2O5Dx = 1.264 Mg m3
Mr = 433.75Melting point = 415–417 K
Hexagonal, P65Cu Kα radiation, λ = 1.5418 Å
Hall symbol: P 65Cell parameters from 21563 reflections
a = 12.1055 (14) Åθ = 3.3–68.2°
c = 26.939 (5) ŵ = 3.85 mm1
V = 3418.8 (8) Å3T = 173 K
Z = 6Needle, colorless
F(000) = 1368.000.30 × 0.01 × 0.01 mm
? # Insert any comments here.
Data collection top
Rigaku R-AXIS RAPID
diffractometer
Rint = 0.097
Detector resolution: 10.00 pixels mm-1θmax = 68.2°
ω scansh = 1414
29240 measured reflectionsk = 1414
4134 independent reflectionsl = 3132
1326 reflections with F2 > 2σ(F2)
Refinement top
Refinement on F2 w = 1/[0.1σ(Fo2) + 2.0]/(4Fo2)
R[F2 > 2σ(F2)] = 0.043(Δ/σ)max < 0.001
wR(F2) = 0.079Δρmax = 1.14 e Å3
S = 1.06Δρmin = 0.65 e Å3
4134 reflectionsAbsolute structure: Flack (1983), 1992 Friedel pairs
263 parametersAbsolute structure parameter: 0.05 (2)
H-atom parameters constrained
Special details top

Refinement. Refinement using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2.0 σ(F2) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl410.70249 (14)0.13892 (18)0.55437 (6)0.0759 (5)
Cl420.78694 (16)0.3511 (2)0.62183 (6)0.0851 (6)
Cl430.53865 (16)0.12709 (19)0.63264 (6)0.0765 (5)
O1010.2252 (4)0.1300 (3)0.61682 (12)0.0587 (10)
O1020.1765 (5)0.0711 (3)0.53796 (13)0.0844 (14)
O2010.1976 (3)0.1218 (3)0.59163 (12)0.0499 (11)
O3010.4220 (3)0.3423 (4)0.53180 (16)0.0664 (13)
O4010.4902 (3)0.2020 (4)0.53375 (12)0.0581 (11)
N2010.0625 (3)0.0564 (4)0.59947 (12)0.0448 (12)
N3010.1778 (3)0.1437 (4)0.51002 (14)0.0439 (12)
C1010.3418 (6)0.2494 (5)0.6070 (2)0.0737 (19)
C1020.3883 (7)0.3026 (7)0.6566 (2)0.098 (2)
C1030.4377 (7)0.2222 (10)0.5836 (3)0.143 (3)
C1040.3139 (13)0.3318 (8)0.5771 (4)0.162 (4)
C1050.1566 (5)0.0495 (5)0.58122 (17)0.0464 (16)
C2010.0292 (4)0.1567 (5)0.56708 (14)0.0380 (13)
C2020.1402 (4)0.1392 (4)0.55772 (18)0.0362 (13)
C2030.0738 (4)0.2865 (4)0.59201 (19)0.0393 (13)
C2040.1523 (5)0.4006 (5)0.5584 (2)0.0568 (17)
C2050.2060 (7)0.5224 (5)0.5901 (2)0.087 (2)
C2060.0732 (6)0.4062 (6)0.5164 (2)0.070 (2)
C3010.2858 (4)0.1316 (5)0.49924 (18)0.0468 (16)
C3020.4038 (4)0.2403 (6)0.52338 (18)0.0470 (16)
C3030.3090 (6)0.1349 (8)0.4433 (2)0.085 (2)
C4010.6029 (5)0.2933 (6)0.5578 (2)0.066 (2)
C4020.6567 (5)0.2319 (7)0.5900 (2)0.0630 (19)
H10.40280.24660.67670.100*
H20.46500.38230.65380.100*
H30.32400.31510.67130.100*
H40.45570.16790.60320.141*
H50.40260.18220.55270.141*
H60.51420.30060.57790.141*
H70.39230.40830.57140.180*
H80.28010.29020.54630.180*
H90.25520.35150.59240.180*
H100.05820.07000.63430.053*
H110.01220.15460.53680.048*
H120.00280.29170.60400.048*
H130.12590.29070.61910.048*
H140.22190.39480.54510.068*
H150.25610.51870.61650.099*
H160.25680.59550.57030.099*
H170.13590.52750.60340.099*
H180.00390.41210.53000.083*
H190.12230.47760.49550.083*
H200.04130.32990.49760.082*
H210.13680.16220.48390.056*
H220.27180.05250.51220.059*
H230.38170.12750.43580.111*
H240.23640.06910.42680.110*
H250.32310.21560.43240.111*
H260.66360.34100.53280.084*
H270.58570.34870.57700.084*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl410.0749 (11)0.1125 (13)0.0685 (9)0.0680 (10)0.0112 (8)0.0066 (8)
Cl420.0596 (9)0.1154 (15)0.0830 (11)0.0457 (10)0.0121 (8)0.0095 (10)
Cl430.0700 (10)0.1015 (12)0.0605 (8)0.0447 (9)0.0191 (7)0.0151 (8)
O1010.065 (2)0.046 (2)0.041 (2)0.0104 (18)0.0005 (18)0.0047 (17)
O1020.111 (3)0.064 (2)0.037 (2)0.012 (2)0.006 (2)0.0059 (19)
O2010.062 (2)0.068 (2)0.0360 (18)0.046 (2)0.0037 (17)0.0142 (17)
O3010.058 (2)0.059 (2)0.087 (3)0.033 (2)0.002 (2)0.009 (2)
O4010.045 (2)0.079 (2)0.065 (2)0.042 (2)0.0083 (17)0.008 (2)
N2010.046 (2)0.057 (2)0.029 (2)0.023 (2)0.0026 (19)0.0044 (19)
N3010.038 (2)0.068 (2)0.033 (2)0.032 (2)0.0010 (17)0.0028 (18)
C1010.067 (4)0.041 (3)0.078 (4)0.000 (3)0.011 (3)0.003 (3)
C1020.083 (5)0.066 (4)0.100 (5)0.005 (3)0.013 (4)0.021 (4)
C1030.041 (4)0.132 (8)0.180 (10)0.012 (4)0.030 (5)0.025 (7)
C1040.166 (11)0.055 (4)0.229 (11)0.028 (5)0.062 (8)0.022 (6)
C1050.047 (3)0.048 (3)0.031 (3)0.014 (2)0.016 (2)0.007 (2)
C2010.039 (2)0.057 (3)0.024 (2)0.028 (2)0.0022 (19)0.005 (2)
C2020.045 (2)0.040 (2)0.030 (2)0.026 (2)0.003 (2)0.007 (2)
C2030.036 (2)0.040 (2)0.044 (2)0.021 (2)0.007 (2)0.004 (2)
C2040.060 (3)0.051 (3)0.059 (3)0.028 (2)0.010 (2)0.021 (2)
C2050.104 (5)0.047 (3)0.097 (5)0.028 (3)0.035 (4)0.017 (3)
C2060.066 (3)0.066 (3)0.074 (4)0.030 (3)0.003 (3)0.015 (3)
C3010.030 (2)0.081 (4)0.037 (2)0.033 (2)0.001 (2)0.003 (2)
C3020.043 (3)0.069 (3)0.038 (2)0.035 (2)0.010 (2)0.011 (2)
C3030.070 (4)0.151 (7)0.056 (3)0.071 (5)0.006 (3)0.010 (3)
C4010.045 (3)0.092 (4)0.074 (4)0.043 (3)0.009 (3)0.001 (3)
C4020.062 (3)0.088 (4)0.050 (3)0.045 (3)0.001 (3)0.006 (3)
Geometric parameters (Å, º) top
Cl41—C4021.766 (9)N301—H210.950
Cl42—C4021.740 (5)C102—H10.950
Cl43—C4021.777 (5)C102—H20.950
O101—C1011.453 (6)C102—H30.950
O101—C1051.323 (5)C103—H40.950
O102—C1051.192 (5)C103—H50.950
O201—C2021.228 (7)C103—H60.950
O301—C3021.163 (9)C104—H70.950
O401—C3021.368 (9)C104—H80.950
O401—C4011.412 (6)C104—H90.950
N201—C1051.312 (5)C201—H110.950
N201—C2011.456 (5)C203—H120.950
N301—C2021.355 (6)C203—H130.950
N301—C3011.418 (8)C204—H140.950
C101—C1021.467 (9)C205—H150.950
C101—C1031.495 (14)C205—H160.950
C101—C1041.448 (16)C205—H170.950
C201—C2021.482 (9)C206—H180.950
C201—C2031.537 (7)C206—H190.950
C203—C2041.523 (6)C206—H200.950
C204—C2051.538 (8)C301—H220.950
C204—C2061.505 (9)C303—H230.950
C301—C3021.522 (6)C303—H240.950
C301—C3031.530 (7)C303—H250.950
C401—C4021.488 (12)C401—H260.950
N201—H100.950C401—H270.950
C101—O101—C105122.7 (4)C101—C103—H6108.9
C302—O401—C401115.6 (5)H4—C103—H5109.5
C105—N201—C201121.2 (3)H4—C103—H6109.5
C202—N301—C301119.9 (4)H5—C103—H6109.4
O101—C101—C102103.8 (4)C101—C104—H7107.3
O101—C101—C103109.4 (6)C101—C104—H8107.9
O101—C101—C104110.0 (7)C101—C104—H9113.1
C102—C101—C103108.1 (7)H7—C104—H8109.5
C102—C101—C104112.0 (7)H7—C104—H9109.5
C103—C101—C104113.0 (8)H8—C104—H9109.5
O101—C105—O102124.3 (4)N201—C201—H11108.6
O101—C105—N201111.5 (3)C202—C201—H11110.7
O102—C105—N201124.2 (4)C203—C201—H11108.3
N201—C201—C202110.5 (5)C201—C203—H12110.5
N201—C201—C203108.8 (3)C201—C203—H13106.0
C202—C201—C203109.9 (3)C204—C203—H12108.5
O201—C202—N301120.3 (5)C204—C203—H13108.2
O201—C202—C201121.9 (4)H12—C203—H13109.5
N301—C202—C201117.7 (4)C203—C204—H14109.3
C201—C203—C204114.1 (4)C205—C204—H14108.4
C203—C204—C205108.2 (4)C206—C204—H14109.1
C203—C204—C206111.4 (4)C204—C205—H15110.1
C205—C204—C206110.4 (6)C204—C205—H16110.3
N301—C301—C302109.8 (5)C204—C205—H17107.9
N301—C301—C303111.4 (5)H15—C205—H16109.5
C302—C301—C303108.5 (4)H15—C205—H17109.5
O301—C302—O401123.3 (4)H16—C205—H17109.5
O301—C302—C301126.8 (6)C204—C206—H18108.7
O401—C302—C301109.9 (6)C204—C206—H19111.2
O401—C401—C402111.7 (5)C204—C206—H20108.5
Cl41—C402—Cl42110.7 (4)H18—C206—H19109.5
Cl41—C402—Cl43107.0 (4)H18—C206—H20109.5
Cl41—C402—C401110.9 (4)H19—C206—H20109.5
Cl42—C402—Cl43110.2 (3)N301—C301—H22108.7
Cl42—C402—C401108.4 (5)C302—C301—H22109.4
Cl43—C402—C401109.7 (4)C303—C301—H22109.0
C105—N201—H10119.0C301—C303—H23111.9
C201—N201—H10119.6C301—C303—H24110.9
C202—N301—H21120.5C301—C303—H25105.5
C301—N301—H21119.4H23—C303—H24109.5
C101—C102—H1111.9H23—C303—H25109.5
C101—C102—H2109.9H24—C303—H25109.5
C101—C102—H3106.6O401—C401—H26107.6
H1—C102—H2109.5O401—C401—H27109.6
H1—C102—H3109.5C402—C401—H26108.5
H2—C102—H3109.5C402—C401—H27109.8
C101—C103—H4113.0H26—C401—H27109.5
C101—C103—H5106.4
C101—O101—C105—O1026.9 (12)N201—C201—C202—O20149.8 (5)
C101—O101—C105—N201174.3 (6)N201—C201—C202—N301130.6 (4)
C105—O101—C101—C102176.9 (7)N201—C201—C203—C204170.0 (5)
C105—O101—C101—C10361.6 (9)C202—C201—C203—C20468.9 (6)
C105—O101—C101—C10463.1 (10)C203—C201—C202—O20170.3 (5)
C302—O401—C401—C402150.4 (5)C203—C201—C202—N301109.3 (4)
C401—O401—C302—O3012.8 (7)C201—C203—C204—C205171.9 (6)
C401—O401—C302—C301178.1 (4)C201—C203—C204—C20666.5 (7)
C105—N201—C201—C20291.6 (6)N301—C301—C302—O30129.1 (7)
C105—N201—C201—C203147.7 (6)N301—C301—C302—O401151.8 (4)
C201—N201—C105—O101177.2 (6)C303—C301—C302—O30192.9 (8)
C201—N201—C105—O1021.6 (11)C303—C301—C302—O40186.2 (6)
C202—N301—C301—C30261.6 (6)O401—C401—C402—Cl4163.2 (5)
C202—N301—C301—C303178.2 (4)O401—C401—C402—Cl42175.1 (4)
C301—N301—C202—O2011.6 (6)O401—C401—C402—Cl4354.8 (6)
C301—N301—C202—C201178.0 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N201—H10···O102i0.951.972.907 (5)171
N301—H21···O201ii0.951.892.829 (6)170
Symmetry codes: (i) y, x+y, z+1/6; (ii) xy, x, z1/6.
 

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